This invention relates to an improved process and apparatus for control of corner shape in continuous or semi-continuous electromagnetic casting of desired shapes such as sheet or rectangular ingots of metals and alloys. The basic electromagnetic casting process has been known and used for many years for continuously or semi-continuously casting metals and alloys.
One of the problems which has been presented by electromagnetic casting of sheet ingots has been the existence of high radius of curvature corners thereon. Rounding off of corners in electromagnetic cast sheet ingots is a result of higher electromagnetic pressure at a given distance from the inductor near the ingot corners, where two proximate faces of the inductor generate a larger field. This is in contrast to the lower pressure at the same distance from the inductor on the broad face of the ingot remote from the corner, where only one inductor face acts.
There is a need to form small radius of curvature corners on sheet ingots so that during rolling cross-sectional changes at the edges of the ingot are minimized. Larger radius of curvature corners accentuate tensile stress at the ingot edges during rolling which causes edge cracking and loss of material. Thus, by reducing the radius of curvature of the ingot at the corners there is a maximizing in the production of useful material.
It has been found in accordance with the present invention that in electromagnetic forming of sheet ingots, enhanced metal flow to the ingot corners resulting in small radius of curvature corners can be accomplished by utilization of a hot-top or open ended container having internal baffles. The hot-top is placed before and adjacent to the electromagnetic casting station and supplies molten metal to said station.
In another embodiment of the present invention enhanced metal flow to the ingot corners is accomplished by utilization of a downspout having multiple nozzles for providing directionality of molten metal to the corners of a hot-top axially aligned with the electromagnetic casting station.
In still yet another embodiment of the present invention enhanced metal flow to ingot corners is accomplished by utilization of a downspout having multiple nozzles for providing directionality of supplied molten metal to the corners of the molten ingot as it is formed in the casting station.